A ZASP Missense Mutation, S196L, Leads to Cytoskeletal and Electrical Abnormalities in a Mouse Model of Cardiomyopathy

作者：Li Zhaohui; Ai Tomohiko; Samani Kaveh; Xi Yutao; Tzeng Huei Ping; Xie Mingxing; Wu Shan; Ge Shuping; Taylor Michael D; Dong Jian Wen; Cheng Jie; Ackerman Michael J; Kimura Akinori; Sinagra Gianfranco; Brunelli Luca; Faulkner Georgine; Vatta Matteo^*

来源：Circulation-Arrhythmia and Electrophysiology, 2010, 3(6): 646-U134.

DOI：10.1161/CIRCEP.109.929240

• ZASP
• Ca(v)1.2
• ACTN2
• telethonin
• Na(v)1.5
• DCM
• arrhythmias
• conduction

Background-Dilated cardiomyopathy (DCM) is a primary disease of the heart muscle associated with sudden cardiac death secondary to ventricular tachyarrhythmias and asystole. However, the molecular pathways linking DCM to arrhythmias and sudden cardiac death are unknown. We previously identified a S196L mutation in exon 4 of LBD3-encoded ZASP in a family with DCM and sudden cardiac death. These findings led us to hypothesize that this mutation may precipitate both cytoskeletal and conduction abnormalities in vivo. Therefore, we investigated the role of the ZASP4 mutation S196L in cardiac cytoarchitecture and ion channel biology.
Methods and Results-We generated and analyzed transgenic mice with cardiac-restricted expression of the S196L mutation. We also performed cellular electrophysiological analysis on isolated S196L cardiomyocytes and protein-protein interaction studies. Ten month-old S196L mice developed hemodynamic dysfunction consistent with DCM, whereas 3-month-old S196L mice presented with cardiac conduction defects and atrioventricular block. Electrophysiological analysis on isolated S196L cardiomyocytes demonstrated that the L-type Ca(2+) currents and Na(+) currents were altered. The pull-down assay demonstrated that ZASP4 complexes with both calcium (Ca(v)1.2) and sodium (Na(v)1.5) channels.
Conclusions-Our findings provide new insight into the mechanisms by which mutations of a structural/cytoskeletal protein, such as ZASP, lead to cardiac functional and electric abnormalities. This work represents a novel framework to understand the development of conduction defects and arrhythmias in subjects with cardiomyopathies, including DCM. (Circ Arrhythm Electrophysiol. 2010;3:646-656.)

• 出版日期2010-12